Webbing take up device

ABSTRACT

In a webbing take-up device, the overall lengths of pistons are set shorter than a separation between bent portions. Moreover, the overall length of a piston is set even shorter than the shorter separation out of a separation between the bent portions, and a separation between bent portions. Pistons do not straddle the bent portion and the bent portion, and do not straddle the bent portion and the bent portion. This enables the pistons to easily arrive at their initial disposed positions inside a cylinder.

TECHNICAL FIELD

The present invention relates to a webbing take-up device provided with a pre-tensioner device that forcibly takes up webbing onto a spool.

BACKGROUND ART

There is a webbing take-up device provided with a pre-tensioner device, in which a moving member, such as a piston or a force transmission element, is formed of a material capable of deforming In such configuration, even if a cylinder such as a guide portion bends or curves partway, the moving member is able to deform following the bent or curved portion of the cylinder (see, for example, the specification of German Patent Application Publication No. 102006031359).

In such a configuration, the moving member is inserted through one end of the cylinder, and disposed at a specific position inside the cylinder; however, the moving member deforms when the moving member has passed the bent portion or the curved portion of the cylinder during this movement. Such deformation of the moving member acts as resistance to movement of the moving member.

SUMMARY OF INVENTION Problem to be Solved by the Invention

In consideration of the above circumstances, an object of the present invention is to obtain a webbing take-up device facilitating insertion of a moving member inside a cylinder.

Means for Solving the Problem

A webbing take-up device of a first aspect of the present invention includes: a spool that takes up a webbing by rotating in a take-up direction; a hollow tube shaped cylinder in which a plurality of bent portions are set at an intermediate portion in an axial line direction of the cylinder, the axial line direction of the cylinder being changed by the bent portions; a plurality of moving members having flexibility, that are disposed in a row along the axial line direction inside the cylinder, the moving members having a shorter length in the axial line direction than a length from a first bent portion to a last bent portion through which the moving members pass from being inserted into the cylinder and until arriving at disposed positions; and a gas generation means that is provided at a base end portion of the cylinder, that supplies gas to the cylinder, and that moves the plurality of moving members toward a leading end side of the cylinder by pressure of the gas and rotates the spool in the take-up direction.

In the webbing take-up device of the first aspect of the present invention, the plural moving members are disposed in lineup along the axial line direction of the cylinder inside the cylinder. The gas generation means is provided at the base end portion of the cylinder, and gas is supplied inside the cylinder due to activation of the gas generation means. The moving members are moved toward the leading end side of the cylinder due to the pressure of the gas. The spool is rotated in the take-up direction, and the webbing is taken up onto the spool from its length direction base end side, due to the moving members moving toward the leading end side of the cylinder in this manner.

In the cylinder, plural bent portions are set, and the axial line direction of the cylinder changes due to the bent portions. Each moving member has a shorter length in the axial line direction than the length from the first bent portion to the last bent portion through which the respective moving member passes between from being inserted into the cylinder to its disposed position. Thus each moving member is not across at least one bent portion during between being inserted through an end portion of the cylinder and being disposed at its disposed position. This enables resistance occurring in each moving member, during between from the moving member being inserted into the cylinder to arriving at its placement position, to be reduced, such that the moving member is easily inserted into the cylinder.

A webbing take-up device of a second aspect of the present invention is the webbing take-up device of the first aspect of the present invention, wherein the length in the axial line direction of each of the plurality of moving members is set to be shorter than an interval between adjacent bent portions which are disposed nearest to each other in the axial line direction, the adjacent bent portions being among the bent portions through which each of the moving members passes from being inserted into the cylinder until arriving at the disposed position.

In the webbing take-up device of the second aspect of the present invention, the length in the axial line direction of the moving member is set shorter than the space between the adjacent bent portions disposed nearest to each other in the axial line direction from out of the bent portions through which the moving member passes during between from being inserted into the cylinder to arriving at its disposed position. Thus the moving member does not straddle two or more bent portions during between being inserted into the cylinder to arriving at its disposed positions. This enables resistance encountered by the moving member during between being inserted into the cylinder to arriving at its disposed position to be reduced, such that the moving member is easily inserted into the cylinder.

A webbing take-up device of a third aspect of the present invention is the webbing take-up device of the second aspect of the present invention, wherein the length in the axial line direction of each of the plurality of moving members is set to be shorter than an interval between adjacent bent portions which are disposed nearest to each other in the axial line direction, the adjacent bent portions being between both axial line direction ends of the cylinder.

In the webbing take-up device of the third aspect of the present invention, the length in the axial line direction of the moving member is shorter than the space between the adjacent bent portions that are nearest to each other in the axial line direction of the cylinder between both axial line direction ends of the cylinder. Thus moving member does not straddle two or more bent portions during between from being inserted into the cylinder to arriving at its disposed position. Moreover, the lengths of respective moving members can be set the same, such that there is no limitation to the sequence in which the moving members are inserted into the cylinder, thereby enabling ease of operation when the moving members are housed inside the cylinder to be improved.

A webbing take-up device of a fourth aspect of the present invention includes: a spool that takes up a webbing by rotating in a take-up direction; a hollow tube shaped cylinder in which a bent portion is set, an axial line direction of the cylinder being changed by the bent portion; a plurality of moving members having flexibility, that are disposed in a row along the axial line direction inside the cylinder, the moving members having a shorter length in the axial line direction than an axial line direction length of the bent portion; and a gas generation means that is provided at a base end portion of the cylinder, that supplies gas to the cylinder, and that moves the plurality of moving members toward a leading end side of the cylinder by pressure of the gas and rotates the spool in the take-up direction.

In the webbing take-up device of the fourth aspect of the present invention, the plural moving members are disposed lineup along the axial line direction of the cylinder inside the cylinder. The gas generation means is provided at the base end portion of the cylinder, and gas is supplied inside the cylinder due to activation of the gas generation means. The moving members move toward the leading end side of the cylinder due to the pressure of the gas. The spool is rotated in the take-up direction, and the webbing is taken up onto the spool from its length direction base end side, due to the moving members moving toward the leading end side of the cylinder in this manner.

In the cylinder, the bent portion is set, and the axial line direction of the cylinder changes due to the bent portion. Each moving member has a shorter length in the axial line direction than the axial line direction length of the bent portion, so there is a small deformation of the moving member when the moving member passes through the bent portion. This enables resistance occurring in the moving member during between from being inserted into the cylinder to arriving at its disposed position to be reduced, such that the moving member is easily inserted into the cylinder.

A webbing take-up device of a fifth aspect of the present invention is the webbing take-up device of the fourth aspect of the present invention, wherein the length in the axial line direction of a moving member disposed at the bent portion of the cylinder becomes shorter on progression toward a side of a center of curvature of the bent portion, and an end face of the moving member disposed at the bent portion of the cylinder is an inclined face with respect to a direction orthogonal to an axis of the moving member in a natural state of the moving member.

In the webbing take-up device of the fifth aspect of the present invention, the length in the axial line direction of the moving member disposed at the bent portion of the cylinder becomes shorter on progression toward the side of the center of curvature of the bent portion. Moreover, in a natural state of the moving member, the end face of the moving member disposed at the bent portion of the cylinder forms an inclined face with respect to a direction orthogonal to the axis of the moving member. This enables a gap between the end faces of the moving members that are adjacent to each other inside the bent portion of the cylinder to be eliminated, or enables such a gap to be reduced. Thus no deformation of the moving members is required so as to fill a gap between adjacent moving members, or such deformation is reduced, when the moving members move due to pressure from the gas. Thus there is an improved response from activation of the gas generation means to movement of the moving members, and, since no gap is required, the cylinder can be shortened by amount corresponding to gap.

A webbing take-up device of a sixth aspect of the present invention is the webbing take-up device of the fourth aspect of the present invention, wherein the moving members that are adjacent inside the bent portion of the cylinder are disposed separated from each other in the axial line direction at an outer side in a direction of a radius of curvature of the bent portion.

In the webbing take-up device of the sixth aspect of the present invention, the adjacent moving members inside the bent portion of the cylinder are disposed separated from each other in the axial line direction at an outer side in a direction of a radius of curvature of the bent portion. Thus even if the moving member deforms due to arriving at the bent portion, such deformation of the moving member is not liable to affect the adjacent moving member.

A webbing take-up device of a seventh aspect of the present invention is the webbing take-up device of the sixth aspect of the present invention, wherein the adjacent moving members inside the bent portion of the cylinder are integrally coupled together by a coupling portion.

In the webbing take-up device of the seventh aspect of the present invention, the adjacent moving members inside the bent portion of the cylinder are integrally coupled together by the coupling portion, thereby forming a gap corresponding to the size of the coupling portion between the adjacent moving members. This enables a gap to be easily formed between the adjacent moving members. Moreover, the plural moving members can be easily inserted into the cylinder due to being integrally coupled together by the coupling portion(s).

A webbing take-up device of an eighth aspect of the present invention is the webbing take-up device of the seventh aspect of the present invention, wherein the coupling portion is broken by the moving members being disposed inside the bent portion.

In the webbing take-up device of the eighth aspect of the present invention, the coupling portion is broken by the moving members being disposed inside the bent portion. The moving member is accordingly not liable to be affected by the coupling portion or other adjacent moving member(s), such that movement inside the cylinder is easier.

Effect of Invention

As explained above, the webbing take-up device according to the present invention facilitates insertion of a moving member into a cylinder.

BRIEF DESCRIPTION OF DRAWINGS

[FIG. 1] A schematic perspective view of a webbing take-up device according to a first embodiment.

[FIG. 2] A perspective view corresponding to FIG. 1, with a cylinder omitted.

[FIG. 3] A schematic plan view of a webbing take-up device according to the first embodiment.

[FIG. 4] A schematic side view of a webbing take-up device according to the first embodiment.

[FIG. 5] A side view corresponding to FIG. 4, illustrating a state in which a moving member has moved to rotate a spool in a take-up direction.

[FIG. 6] An enlarged plan view illustrating a moving member of a webbing take-up device according to a second embodiment.

[FIG. 7] An enlarged plan view illustrating a moving member of a webbing take-up device according to a third embodiment.

[FIG. 8] An enlarged side view illustrating a moving member of a webbing take-up device according to a fourth embodiment.

[FIG. 9] An enlarged side view illustrating a moving member of a webbing take-up device according to a fifth embodiment.

[FIG. 10] An enlarged side view illustrating a moving member of a webbing take-up device according to a sixth embodiment.

[FIG. 11] A side view of an elongated member that is the base member of a moving member.

[FIG. 12] An enlarged side view illustrating a moving member of a webbing take-up device according to a seventh embodiment.

EMBODIMENTS FOR CARRYING OUT THE INVENTION Configuration of First Embodiment

As shown in FIG. 1 to FIG. 4, a webbing take-up device 10 according to a first embodiment includes a frame 12. The frame 12 includes a substantially flat plate shaped back plate 14. Leg plates 16 and 18 extend out from both width direction ends of the back plate 14 toward one side in the thickness direction of the back plate 14. A spool 20 is provided between the leg plate 16 and the leg plate 18 of the frame 12. The spool 20 is supported by the leg plates 16 and 18, either directly, or indirectly through another member, so as to be capable of rotating about an axis with the facing direction of the leg plates 16 and 18 as its axial direction. A length direction base end side of elongated belt shaped webbing 24 is anchored to the spool 20, and when the spool 20 rotates in a take-up direction about a central axial line, the webbing 24 is taken up onto the spool 20 from the length direction base end side.

The spool 20 is configured in a hollow shape open at both axial direction end portions thereof. A torsion shaft (not shown in the drawings), serving as an energy absorption section configuring a force limiter mechanism, is provided inside the spool 20. A lock base, configuring a lock mechanism, is provided at the leg plate 16 side of the spool 20, and the lock base is rotatably inserted into the open end at the leg plate 16 side of the spool 20. The torsion shaft is coupled to the lock base at the leg plate 16 side, in a state in which rotation relative to the lock base is restricted.

The lock mechanism is provided with a sensor that activates when the vehicle enters a rapid deceleration state, or when the rotation acceleration rate of the lock base in a pull-out direction, this being the opposite direction to the take-up direction described above, exceeds a specific magnitude, and rotation of the lock base in the pull-out direction is restricted when the sensor activates.

A coupling member 32 is inserted into an open end at the leg plate 18 side of the spool 20. Rotation of the coupling member 32 relative to the spool 20 is restricted. An end portion of the torsion shaft at the leg plate 18 side is connected to the coupling member 32, in a state in which relative rotation to the coupling member 32 is restricted. Thus relative rotation of the lock base to the spool 20 is restricted through the torsion shaft, and rotation of the spool 20 in the pull-out direction is restricted when the sensor of the lock mechanism activates and rotation of the lock base in the pull-out direction is restricted.

The webbing take-up device 10 includes a pre-tensioner device 42. The pre-tensioner device 42 includes a cylinder 44. The cylinder 44 includes a general portion 46A. The general portion 46A is formed in a circular cross-section tube shape with its central axial line direction running along the thickness direction of the back plate 14, and is provided so as to run along the leg plate 16 near an upper end portion of the leg plate 16 at the outside of the leg plate 16 (the opposite side of the leg plate 16 to the leg plate 18). A gas generator 48, serving as a gas generation means, is provided at a base end portion of the leg plate 16 (an end portion at the back plate 14 side). The gas generator 48 is electrically connected to a control means such as an ECU, and the gas generator 48 is activated when the vehicle rapidly decelerates, supplying gas inside the cylinder 44 from a base end side of the general portion 46A.

A bent portion 50A is formed contiguously to the general portion 46A at a leading end of the general portion 46A. An inner diameter dimension of the bent portion 50A is substantially the same as an inner diameter dimension of the general portion 46A, and the bent portion 50A configures a tube shape with a bent or curved central axial line thereof. The central axial line direction of the cylinder 44 heads toward the leg plate 18 side at the bent portion 50A so as to run along the width direction of the back plate 14. A general portion 46B is formed contiguously to the bent portion 50A at the opposite side to the general portion 46A.

The general portion 46B configures a tube shape with its central axial line running along the width direction of the back plate 14, and an inner diameter dimension of the general portion 46B is substantially the same as the inner diameter dimension of the general portion 46A. The general portion 46B is provided at the lateral side of end portions of the leg plates 16 and 18 at the opposite side to the back plate 14, and a bent portion 50B is formed contiguously to the general portion 46B at the opposite side to the bent portion 50A.

An inner diameter dimension of the bent portion 50B is substantially the same as the inner diameter dimension of the general portion 46A, and the bent portion 50B configures a tube shape with a bent or curved central axial line thereof. The central axial line direction of the cylinder 44 heads toward the thickness direction of the back plate 14 at the bent portion 50B. A general portion 46C is formed contiguously to the bent portion 50B at the opposite side to the general portion 46B.

The general portion 46C is formed in a tube shape with its central axial line direction running along the extension direction of the leg plate 18 from the back plate 14, and an inner diameter dimension of the general portion 46C is substantially the same as the inner diameter dimension of the general portion 46A. The general portion 46C is provided so as to run along the leg plate 18 near an upper end portion of the leg plate 18 at the outside of the leg plate 18 (the opposite side of the leg plate 18 to the leg plate 16), and a bent portion 50C is formed contiguously to the general portion 46C at the opposite side to the bent portion 50B.

An inner diameter dimension of the bent portion 50C is substantially the same as the inner diameter dimension of the general portion 46A, and the bent portion 50C configures a tube shape with a bent or curved central axial line thereof. At the bent portion 50C, the central axial line direction of the cylinder 44 heads toward a substantially central side of the leg plate 18 (namely, downward on the leg plate 18 and toward a leading end side in the extension direction of the leg plate 18 from the back plate 14). A general portion 46D is formed contiguously to the bent portion 50C at the opposite side to the general portion 46C.

The general portion 46D is formed in a tube shape with its central axial line direction heading downward on the leg plate 18 and toward the leading end side in the extension direction of the leg plate 18 from the back plate 14, and an inner diameter dimension of the general portion 46D is substantially the same as the inner diameter dimension of the general portion 46A. A leading end of the general portion 46D is open. A case 52, with an open upper end, is provided below the leading end of the general portion 46D.

As shown in FIG. 3 and FIG. 4, pistons 58A to 58E are provided inside the cylinder 44 that bends as appropriate at the bent portions 50A to 50C. Each of the pistons 58A to 58E is formed in a circular column shape with an outer diameter dimension substantially the same as the inner diameter dimension of the cylinder 44, using a flexible synthetic resin material such as nylon (PA), polyvinyl chloride (PVC), or an elastomer.

From out of the pistons 58A to 58E, the piston 58A is provided furthest toward a base end side inside the cylinder 44 (namely, the gas generator 48 side). In its initial disposed position, a leading end side of the piston 58A intrudes into the bent portion 50A, and the leading end side of the piston 58A bends or curves following the bent portion 50A. The piston 58B is provided beside a leading end portion of the piston 58A. In its initial disposed position, the entire piston 58B is disposed inside the general portion 46B.

The piston 58C is provided beside a leading end portion of the piston 58B. In its initial disposed position, an intermediate portion of the piston 58C is positioned inside the bent portion 50B, and the intermediate portion of the piston 58C bends or curves following the bent portion 50B. The piston 58D is provided beside a leading end portion of the piston 58C. In its initial disposed position, the entire piston 58D is disposed inside the general portion 46C.

The piston 58E is provided beside a leading end portion of the piston 58D. In its initial disposed position, a leading end side of the piston 58E is positioned inside the general portion 46D, and a base end side thereof is positioned inside the bent portion 50C. The base end side of the piston 58E thereby bends or curves following the bent portion 50C.

Supplementary explanation follows regarding the respective overall lengths of the pistons 58C to 58E (the lengths from the base end portion to the leading end portion in the central axial line direction).

The respective overall lengths of the piston 58C and the piston 58D are set shorter than a separation from the bent portion 50A to the bent portion 50B. Thus the piston 58C and the piston 58D do not straddle both the bent portion 50A and the bent portion 50B when the piston 58C and the piston 58D are each inserted through the base end portion of the cylinder 44 and moved to their respective initial disposed positions.

The overall length of the piston 58E is set even shorter than the shorter separation, which is out of the separation from the bent portion 50A to the bent portion 50B and the separation from the bent portion 50B to the bent portion 50C. Thus the piston 58E does not straddle both the bent portion 50A and the bent portion 50B, and does not straddle both the bent portion 50B and the bent portion 50C.

When the gas generator 48 activates and gas is supplied between the gas generator 48 and the base end portion of the piston 58A, the piston 58A moves toward a leading end side of the cylinder 44. The piston 58A that has moved in this manner presses against the piston 58B, and moves the piston 58B toward the leading end side of the cylinder 44. Thus the pistons 58A to 58E moving in this manner feed out and drop from the leading end of the cylinder 44 in sequence starting from the piston 58E, and are collected inside the case 52.

Plural rotating teeth 62 are provided beside the leading end of the cylinder 44. The rotating teeth 62 are integrally formed to the coupling member 32, and extend out in a radial shape from a rotation center side of the coupling member 32 toward the outside. When the pistons 58A to 58E move due to pressure of the gas generated by the gas generator 48, first, leading ends of the rotating teeth 62 dig in so as to bite into the piston 58E. When the piston 58E moves further in this state, the rotating teeth 62 rotate in the take-up direction.

Operation and Effect of Present Embodiment

In the webbing take-up device 10 with the above configuration, when the gas generator 48 activates in a state in which the webbing 24 is worn over the body of an occupant seated in a seat applied with the webbing take-up device 10, the piston 58A moves toward the leading end side of the cylinder 44, and the piston 58A also presses the piston 58B toward the leading end side of the cylinder 44 in the manner described above. When the pistons 58A to 58E move in this manner, the rotating teeth 62 first dig into the piston 58E.

When the pistons 58A to 58E move further in this state, as described above, the piston 58E rotates the rotating teeth 62 in the take-up direction. Then, when the pistons 58A to 58E move further from this state, as described above, as shown in FIG. 5, the piston 58E drops and the piston 58E is collected in the case 52, the rotating teeth 62 dig into the piston 58D, and the moving piston 58D further rotates the rotating teeth 62 in the take-up direction.

In this manner, the rotating teeth 62 are rotated in the take-up direction while the rotating teeth 62 dig into the piston 58E to the piston 58A in sequence. The rotating teeth 62 are formed to the coupling member 32, and relative rotation of the coupling member 32 to the spool 20 is restricted. Thus when the rotating teeth 62 are rotated in the take-up direction, the spool 20 is rotated in the take-up direction, and the webbing 24 is thereby taken up onto the spool 20. Looseness (what is referred to as “slack”) of the webbing 24 worn over the body of the occupant is eliminated, and the body of the occupant is restrained by the webbing 24 with a stronger force than previously.

In the webbing take-up device 10, each of the pistons 58A to 58E is formed from a flexible synthetic resin material, as described above. This enables the pistons 58A to 58E to be provided inside the cylinder 44, which is bent or curved at the bent portions 50A to 50C, and also enables the pistons 58A to 58E to be moved inside the thus bent or curved cylinder 44. This enables the cylinder 44 to be prevented or suppressed from protruding out greatly toward the outside of the frame 12 in a case of setting sufficient length for the cylinder 44. This enables the overall webbing take-up device 10 to be made small.

As described above, the pistons 58A to 58E are inserted through the base end portion of the cylinder 44, and the respective overall lengths of the piston 58C and the piston 58D are set shorter than the separation from the bent portion 50A to the bent portion 50B. Thus, when the piston 58C and the piston 58D are each inserted through the base end portion of the cylinder 44 and moved to their respective initial disposed positions, the piston 58C and the piston 58D do not straddle both the bent portion 50A and the bent portion 50B.

This enables resistances, which the piston 58C and the piston 58D respectively receive from an inner circumferential portion of the cylinder 44, to be reduced prior to the piston 58C and the piston 58D arriving at their respective initial disposed positions. This enables the piston 58C and the piston 58D to be easily moved to their respective initial disposed positions, and facilitates an insertion operation of the piston 58C and the piston 58D inside the cylinder 44.

The overall length of the piston 58E is set even shorter than the shorter separation among the separation from the bent portion 50A to the bent portion 50B, and the separation from the bent portion 50B to the bent portion 50C. Thus the piston 58E does not straddle both the bent portion 50A and the bent portion 50B, and does not straddle both the bent portion 50B and the bent portion 50C.

This enables resistance, which the piston 58E receives from the inner circumferential portion of the cylinder 44, to be reduced prior to the piston 58E arriving at its initial disposed position. This enables the piston 58E to be easily moved to its initial disposed position, and facilitates the insertion operation of the piston 58E inside the cylinder 44.

Note that, although only the overall lengths of the pistons 58C to 58E have been referred to in the above explanation of the present embodiment, for example, the pistons 58A to 58E may all be set shorter than the shorter separation out of the separation from the bent portion 50A to the bent portion 50B, and the separation from the bent portion 50B to the bent portion 50C.

By setting in this manner, when the pistons 58A to 58E are moved through the base end portion of the cylinder 44 to their initial disposed positions, and also when the pistons 58A to 58E are moved due to pressure of the gas from the gas generator 48, none of the pistons 58A to 58E straddle both the bent portion 50A and the bent portion 50B, or straddle both the bent portion 50B and the bent portion 50C. The enables the pistons 58A to 58E to be easily moved when the pistons 58A to 58E are moved through the base end portion of the cylinder 44 to their initial disposed positions, and also when the pistons 58A to 58E are moved due to pressure of the gas from the gas generator 48.

The overall lengths of each of the pistons 58A to 58E may be set at the same length, with such a configuration enabling the specification for the pistons 58A to 58E to be unified, and enabling the cost to be reduced.

For example, a moving member may be set longer than the separation between the bent portion 50A and the bent portion 50B, and the separation between the bent portion 50B and the bent portion 50C, along the central axial line of the cylinder 44, and be set shorter than a separation between the bent portion 50A and the bent portion 50C along the central axial line of the cylinder 44. Even such a configuration also enables the moving member to arrive at its initial disposed position more easily than in a configuration in which a moving member straddles all of the bent portions 50A to 50C.

Although there is no particular mention regarding the rigidity of each of the pistons 58A to 58E in the above explanation, the rigidity of each of the pistons 58A to 58E may be uniform, or may be different from each other.

In the present exemplary embodiment, the central axial line of each of the general portions 46A to 46D of the cylinder 44 is a straight line shape; however the general portions 46A to 46D may be configured as curved, as long as the radius of curvature is sufficiently greater than the bent portions 50A to 50C, and the pistons 58A to 58E do not receive much larger resistance when passing through the inside thereof.

The present embodiment is configured such that the lock mechanism is provided to the frame 12 on the opposite side to the rotating teeth 62; however, the lock mechanism may be provided to the frame 12 on the same side as the rotating teeth 62.

Explanation follows regarding other embodiments of the present invention. Note that, in the explanation of each embodiment below, the same reference numerals are applied to locations that are basically the same as those in previously explained embodiments, including the first embodiment, and detailed explanation thereof is omitted.

Second Embodiment

As shown in FIG. 6, in a webbing take-up device 70, a circular conical shaped, or circular truncated cone shaped protrusion 72 is formed projecting out at one of a base end portion or a leading end portion (the leading end portion in FIG. 6) of a piston 58. A recess 74 is formed at the other of the base end portion or the leading end portion (the base end portion in FIG. 6) of the piston 58, and the protrusion 72 of the piston 58 can enter into the recess 74 of an adjacent piston 58. Such a configuration enables the pistons 58 to be prevented or suppressed from disconnecting from each other when the rotating teeth 62 dig in between the pistons 58 which are adjacent.

Third Embodiment

As shown in FIG. 7, in a webbing take-up device 80 according to a third embodiment, the protrusion 72 and the recess 74 of the piston 58 are formed in a semispherical shape, and the protrusion 72 of the piston 58 can enter into the recess 74 of the adjacent piston 58. This configuration enables similar effects to the second embodiment to be obtained.

Fourth Embodiment

As shown in FIG. 8, in a webbing take-up device 90 according to a fourth embodiment, substantially circular column shaped pistons 58 are disposed in a bent portion 50 of the cylinder 44. The length in the central axial line direction of the piston 58 disposed inside the bent portion 50 is set sufficiently shorter than the length in the central axial line direction of the bent portion 50, enabling plural pistons 58 to be disposed inside the bent portion 50. In a case in which the length in the central axial line direction of each piston 58 is sufficiently shorter than the length in the central axial line direction of the bent portion 50 in this manner, there is small deformation of the piston 58 inside the bent portion 50, or there is no deformation of the piston 58 inside the bent portion 50. This enables the pistons 58 to be easily disposed inside the cylinder 44 including the bent portion 50.

Fifth Embodiment

As shown in FIG. 9, in a webbing take-up device 100 according to a fifth embodiment, pistons 102, serving as moving member, are disposed inside the bent portion 50 of the cylinder 44 instead of the pistons 58. The length in the axial line direction of the piston 102 gradually shortens on progression toward a side of a center of curvature inside the bent portion 50, end faces of the piston 102 are inclined with respect to a direction orthogonal to the axis of the piston 102 in a natural state thereof, and the center of curvature P of the bent portion 50 is preferably positioned on an extension line of the end face of the piston 102.

When gas generated in the gas generator 48 (not shown in FIG. 9) is supplied to the cylinder 44, the piston 102 deforms due to the pressure of the gas so as to fill a gap between the piston and the adjacent piston 102, and presses the adjacent piston 102. Note that in the webbing take-up device 100, the length in the axial line direction of the piston 102 gradually shortens on progression toward the side of the center of curvature inside the bent portion 50, the end faces of each piston 102 slope with respect to the direction orthogonal to the axis of the piston 102 in a natural state, and the center of curvature P of the bent portion 50 is preferably positioned on the extension lines of the end faces of the piston 102. Thus the gap between adjacent pistons 102 is reduced, or the gap between adjacent pistons 102 disappears. Thus there is small deformation, or no deformation, of the pistons 102 in order to fill the gap. Thus there is a quicker response from activation of the gas generator 48 to movement of the pistons 102. Moreover, since there is only a small gap between adjacent pistons 102, or there is no such gap, the length in the central axial line direction of the cylinder 44 can be shortened.

Sixth Embodiment

As shown in FIG. 10, in a webbing take-up device 110 according to a sixth embodiment, adjacent pistons 58 are coupled together by a coupling portion 112. The coupling portion 112 is formed with a sufficiently shorter outer diameter dimension than the piston 58, and the coupling portion 112 is formed of the same material as the piston 58. As shown in FIG. 11, the plural pistons 58 and coupling portions 112 are formed by an elongated member 114 with a circular shaped cross-section. Outer peripheral portions of the elongated member 114 are cut away at suitable positions of a length direction intermediate portion of the elongated member 114 (portions at ranges M between double-dotted dashed lines L1 and lines L2 in FIG. 11). As shown in FIG. 10, the cutaway portion thereby forms the coupling portion 112 that has a shorter outer diameter dimension than other portions, and both sides thereof form the pistons 58.

Thus in the present embodiment, at the adjacent pistons 58 on the outside of the radius of curvature of the bent portion 50, a gap, corresponding to the length of the coupling portion 112, between adjacent pistons 58, are formed. Thus even if the piston 58 deforms due to the pistons 58 being disposed inside the bent portion 50, the piston 58 are not liable to affect the adjacent piston 58, enabling the pistons 58 to move smoothly due to pressure from the gas generated by the gas generator 48 (not shown in FIG. 10).

In the present embodiment, the plural pistons 58 are integrally coupled by the coupling portions 112, enabling the plural pistons 58 to be easily inserted into the cylinder 44, and to arrive at their initial disposed positions.

In the present embodiment, the outer peripheral portions of the elongated member 114 are cut away to form the coupling portions 112, and both sides of the coupling portion 112 form the pistons 58. However, there is not particular limitation to the manufacturing method, and various manufacturing methods may be applied, such as integrally forming the pistons 58 and the coupling portions 112 using a mold.

For example, a configuration may be applied in which a cutting tool such as a cutter is abutted to the outer peripheral portions of the elongated member 114, and at least one of the elongated member 114 or the cutting tool is rotated about the central axial line of the elongated member 114, to form cutouts that do not reach near the central axial line of the elongated member 114. In such a configuration, the coupling portion 112 is a portion which is further to the central axial line portion side of the elongated member 114 than the portion where the cutout is formed, and the pistons 58 are formed to the elongated member 114 at both sides of the cutout along the length direction of the elongated member 114. In such a configuration, there is no particular limitation to the shape of the cutouts, and the shape of the cutouts may be a stripe shape, or may be formed with a triangular shaped cross-section in which the opening width narrows on progression toward the central axial line side.

Seventh Embodiment

As shown in FIG. 12, in a webbing take-up device 120 according to a seventh embodiment, when the pistons 58 are disposed inside the bent portion 50 of the cylinder 44, the coupling portions 112 break due to being pulled, compressed, or the like by the pistons 58. Thus, when the pistons 58 move due to pressure from the gas generated by the gas generator 48 (not shown in FIG. 12), the pistons 58 can move smoothly since the pistons 58 are less liable to be affected by the coupling portions 112.

Explanation of the Reference Numerals

-   10 webbing take-up device -   20 spool -   24 webbing -   44 cylinder -   48 gas generator (gas generation means) -   50 bent portion -   50A bent portion -   50B bent portion -   50C bent portion -   58 piston (moving member) -   58A piston (moving member) -   58B piston (moving member) -   58C piston (moving member) -   58D piston (moving member) -   58E piston (moving member) -   70 webbing take-up device -   80 webbing take-up device -   90 webbing take-up device -   100 webbing take-up device -   102 piston (moving member) -   110 webbing take-up device -   120 webbing take-up device 

1. A webbing take-up device comprising: a spool that takes up a webbing by rotating in a take-up direction; a hollow tube shaped cylinder in which a plurality of bent portions are set at an intermediate portion in an axial line direction of the cylinder, the axial line direction of the cylinder being changed by the bent portions; a plurality of moving members having flexibility, that are disposed in a row along the axial line direction inside the cylinder, the moving members having a shorter length in the axial line direction than a length from a first bent portion to a last bent portion through which the moving members pass from being inserted into the cylinder and until arriving at disposed positions; and a gas generation means that is provided at a base end portion of the cylinder, that supplies gas to the cylinder, and that moves the plurality of moving members toward a leading end side of the cylinder by pressure of the gas and rotates the spool in the take-up direction.
 2. The webbing take-up device of claim 1, wherein the length in the axial line direction of each of the plurality of moving members is set to be shorter than an interval between adjacent bent portions which are disposed nearest to each other in the axial line direction, the adjacent bent portions being among the bent portions through which each of the moving members passes from being inserted into the cylinder until arriving at the disposed position.
 3. The webbing take-up device of claim 2, wherein the length in the axial line direction of each of the plurality of moving members is set to be shorter than an interval between adjacent bent portions which are disposed nearest to each other in the axial line direction, the adjacent bent portions being between both axial line direction ends of the cylinder.
 4. A webbing take-up device comprising: a spool that takes up a webbing by rotating in a take-up direction; a hollow tube shaped cylinder in which a bent portion is set, an axial line direction of the cylinder being changed by the bent portion; a plurality of moving members having flexibility, that are disposed in a row along the axial line direction inside the cylinder, the moving members having a shorter length in the axial line direction than an axial line direction length of the bent portion; and a gas generation means that is provided at a base end portion of the cylinder, that supplies gas to the cylinder, and that moves the plurality of moving members toward a leading end side of the cylinder by pressure of the gas and rotates the spool in the take-up direction.
 5. The webbing take-up device of claim 4, wherein: the length in the axial line direction of a moving member disposed at the bent portion of the cylinder becomes shorter on progression toward a side of a center of curvature of the bent portion, and an end face of the moving member disposed at the bent portion of the cylinder is an inclined face with respect to a direction orthogonal to an axis of the moving member in a natural state of the moving member.
 6. The webbing take-up device of claim 4, wherein the moving members that are adjacent inside the bent portion of the cylinder are disposed separated from each other in the axial line direction at an outer side in a direction of a radius of curvature of the bent portion.
 7. The webbing take-up device of claim 6, wherein the adjacent moving members inside the bent portion of the cylinder are integrally coupled together by a coupling portion.
 8. The webbing take-up device of claim 7, wherein the coupling portion is broken by the moving members being disposed inside the bent portion. 